Platelet-rich plasma injection in the treatment of patellar tendinopathy: a systematic review and meta-analysis.

Purpose: The objective of the study was to assess the efficacy of autologous platelet-rich plasma (PRP) injections in the treatment of patellar tendinopathy.

Methods: The PubMed, MEDLINE, EMBASE, CINAHL, and Cochrane Central Register of Controlled Trials databases were searched for clinical trials which compared PRP injection with other 'active treatment' interventions ('Non-PRP' injection and 'No-injection' treatments) or 'No-active treatment' interventions. Randomized and non-randomized clinical trials that had been published up to 15 November 2021, were included in the meta-analysis. The primary outcome, pain relief, was measured on a 'visual analog scale.' Secondary outcomes were knee functional activities and quality of life (QoL). The PRISMA guidelines were followed throughout the study.

Results: Eight comparative studies were identified for inclusion in the meta-analysis. Assessment of these studies revealed that there were no significant differences in pain relief, functional outcomes, and QoL in the short, medium, and long term between PRP injection and Non-PRP injection interventions. Similarly, comparison of PRP injection to the No-active treatment intervention showed no differences in short- and medium-term pain relief. However, when PRP injection was compared to the No-injection treatment intervention extracorporeal shock wave therapy (ECWT), the former was found to be more effective in terms of pain relief in the medium term (mean difference [MD] - 1.50; 95% confidence interval [CI] - 2.72 to - 0.28) and long term (MD - 1.70; 95% CI, - 2.90 to - 0.50) and functional outcomes in the medium term (MD 13.0; 95% CI 3.01-22.99) and long term (MD 13.70; 95% CI 4.62-22.78).

Conclusions: In terms of pain relief and functional outcomes, the PRP injection did not provide significantly greater clinical benefit than Non-PRP injections in the treatment of patellar tendinopathy. However, in comparison with ESWT, there was a significant benefit in favor of PRP injection.